Cannot delete my old number from top of contacts list

iPhone 5S using iOS 9.1, Set-up phone with temporary number from new supplier, received original number after pac number was recognised, but contacts showing old number, how do I change to original number???

Welcome to iMore! Are you talking about your card at the top of your contact list (see image)? If so you need to scroll down to your contact card located within your contacts and update your information.